Finding the Fourth Proportional to 1,388.18, 1,915.42 and 798.74

Step by Step Solution

1. Step 1: Write the proportion equation
   1,388.18 : 1,915.42 = 798.74 : x
2. Step 2: Convert to fraction form
   1,388.18/1,915.42 = 798.74/x
3. Step 3: Cross multiply
   1,388.18x = 1,915.42 × 798.74
4. Step 4: Simplify right side
   1,388.18x = 1,529,922.57
5. Step 5: Solve for x
   x = 1,529,922.57/1,388.18
6. Step 6: Final answer
   x = 1,102.11